We investigate dietary factors in cohort studies and nutrition related biomarkers in nested case controls studies within the PLCO screeening trial cohort. The dietary factors have included glycemic index and folate. Biomarkers studies have included vitamin D, helicobacter pylori, and insulin like growth factors and insulin resistance factors. Thus far our vitamin D studies have been published. Experimental evidence suggests vitamin D has anticarcinogenic properties; however, a nested-case control study conducted in a population of male Finnish smokers found that higher 25-hydroxyvitamin D (25(OH)D), the best indicator of vitamin D status as determined by the sun and diet, was associated with a significant 3-fold increased risk for pancreatic cancer. We conducted a nested case-control study in the Prostate, Lung, Colorectal, Ovarian Screening Trial cohort of men and women 55-74 years of age at baseline, to test whether pre-diagnostic serum 25(OH)D concentrations were associated with pancreatic cancer risk. Between 1994 and 2006, 184 incident cases of pancreatic adenocarcinoma occurred (follow-up to 11.7 years). Two controls (n=368) who were alive at the time the case was diagnosed, were selected for each case and matched by age, race, sex, and calendar date of blood draw (to control for seasonal variation). We calculated odds ratios (ORs) and 95% confidence intervals (CI) using conditional logistic regression, adjusting for smoking and body mass index. Vitamin D concentrations were not associated with pancreatic cancer overall (highest vs. lowest quintile, >82.3 vs. < 45.9 nmol/L: OR=1.45, 95% CI 0.66-3.15, p-trend=0.49). However, positive associations were observed among subjects with low estimated annual residential solar UBV exposure (highest vs. lowest quartile, OR=4.03, 95% CI 1.38-11.79), but not among those with moderate to high annual exposure (p-interaction=0.02). We did not confirm the previous strong positive association between 25(OH)D and pancreatic cancer, however the increased risk among participants with low residential UVB exposure is similar. We investigate dietary factors in cohort studies and nutrition related biomarkers in nested case controls studies within the PLCO screeening trial cohort. The dietary factors have included glycemic index and folate. Biomarkers studies have included vitamin D, helicobacter pylori, and insulin like growth factors and insulin resistance factors. Thus far our vitamin D studies have been published. Experimental evidence suggests vitamin D has anticarcinogenic properties; however, a nested-case control study conducted in a population of male Finnish smokers found that higher 25-hydroxyvitamin D (25(OH)D), the best indicator of vitamin D status as determined by the sun and diet, was associated with a significant 3-fold increased risk for pancreatic cancer. We conducted a nested case-control study in the Prostate, Lung, Colorectal, Ovarian Screening Trial cohort of men and women 55-74 years of age at baseline, to test whether pre-diagnostic serum 25(OH)D concentrations were associated with pancreatic cancer risk. Between 1994 and 2006, 184 incident cases of pancreatic adenocarcinoma occurred (follow-up to 11.7 years). Two controls (n=368) who were alive at the time the case was diagnosed, were selected for each case and matched by age, race, sex, and calendar date of blood draw (to control for seasonal variation). We calculated odds ratios (ORs) and 95% confidence intervals (CI) using conditional logistic regression, adjusting for smoking and body mass index. Vitamin D concentrations were not associated with pancreatic cancer overall (highest vs. lowest quintile, >82.3 vs. < 45.9 nmol/L: OR=1.45, 95% CI 0.66-3.15, p-trend=0.49). However, positive associations were observed among subjects with low estimated annual residential solar UBV exposure (highest vs. lowest quartile, OR=4.03, 95% CI 1.38-11.79), but not among those with moderate to high annual exposure (p-interaction=0.02). We did not confirm the previous strong positive association between 25(OH)D and pancreatic cancer, however the increased risk among participants with low residential UVB exposure is similar.